Secure attachment of steering wheel to steering shaft

ABSTRACT

A unique and simple method for attaching a steering wheel to a steering shaft includes a pair of securement members. The steering shaft is provided with a slot extending into an enlarged space. The first securement member extends across a bore in the steering wheel, and is threadably received in the second securement member. The steering wheel can be moved onto the steering shaft with the first securement member moving through the slot and into the space. The first securement member can then draw the second securement member into the space. Preferably, there is a tapered interface between the second securement member, the steering wheel, and the steering shaft. The tapered surface drives the steering wheel downwardly onto the steering shaft such that a wedge-lock is provided. In a further feature of this invention, an outer housing surrounds the steering shaft. The outer housing has a pair of spaced slots. The spaced slots selectively provide access to the securement members such that the steering wheel may be removable from the steering shaft, when desired. However, when the steering shaft is locked, the slots are not aligned with the securement members. This will deter theft of the steering wheel assembly. The present invention is particularly useful for modular steering wheel assemblies which incorporate an air bag into the steering wheel.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a simple apparatus and method forsecuring a steering wheel to a steering shaft, and further to a methodand apparatus for preventing theft of the steering wheel.

[0002] In the prior art, steering wheels have traditionally beenattached to a steering shaft prior to attachment of the air bag.Typically, the steering wheel was attached to the steering shaft by abolt or a nut if the shaft is threaded. The air bag was then attached tothe steering wheel module which included a cover, air bag and inflator.

[0003] More recently, there has been an effort to produce so-called“modular” steering wheel and air bag assemblies. These assemblies useattachment techniques that allow the combined air bag module andsteering wheel to be attached to the steering shaft as a pre-assembledmodular unit.

[0004] In general, the prior art methods of attaching modular steeringwheel assemblies to the steering shafts have been complex. Further, themethods have been relatively expensive, bulky and inelegant. Generally,the attachment methods rely on threaded connections between the steeringshaft and the steering wheel hub. Typically, some form of a threadedmember is driven relative to the hub and steering shaft to drive the hubonto the steering shaft.

[0005] These connections have typically been driven from the side of thehub, and have required access to be provided to the threaded member. Airbag theft is becoming an increasing problem. With modular steering wheelassemblies, there is an increased likelihood of theft of the steeringwheel. With the prior art modular steering wheel proposals, since therehas needed to be access to the threaded member, there is also access fora thief which would facilitate the removal of the steering wheel. Thisis, of course, undesirable.

SUMMARY OF THE INVENTION

[0006] In a disclosed embodiment of this invention, the steering wheelhub is attached to the steering shaft by providing the steering shaftwith a slot extending from an end of the shaft, and leading into anenlarged securement space. A first securement member extends across abore in the hub, and is received to draw a second securement member intothe bore. The first securement member is preferably of a relativelysmall dimension, and fits through the slot in the steering shaft. Thesecond securement member is preferably of a greater dimension, and doesnot fit through the slot. When the hub is placed on the steering shaft,the first securement member passes through the slot and into theenlarged space. The first securement member then draws the secondsecurement member into the space. The second securement member thuslocks the steering shaft onto the hub member. Tapered interface surfacesbetween the steering shaft and hub are forced together to provide a“wedge lock”, as described below.

[0007] The present invention thus provides a secure connection in arelatively small space.

[0008] In a preferred embodiment, the first securement member isexternally threaded and the second securement member is internallythreaded. The second securement member is preferably also tapered froman end remote from the space, and becoming smaller toward an endadjacent the securement space. This tapered surface rides along a matingtapered surface within the steering shaft. Thus, as the secondsecurement member moves into the space, it forces the hub downwardlyonto the shaft such that a wedge lock occurs. After connection, shouldone of the first or second securement members come loose or break, thereis still a secure connection from the wedge lock.

[0009] In a further feature of this invention, a removal portion extendswithin the hub and across an upper surface of the steering shaft. Theremoval portion is preferably also provided by a threaded removal memberand a tapered removal member. The taper action is reversed from thesecurement members such that as the threaded removal member draws thetapered removal member across an end surface of the steering shaft, thehub is forced upwardly off of the shaft, breaking the wedge lock. Thefirst and second securement members preferably must be released orremoved before the removal members can break the wedge lock.

[0010] The two structures (i.e., securement and removal) in combinationprovide a very inexpensive, compact, yet reliable way of securing andremoving the steering wheel from the steering shaft. The structuresprovide improvements over the prior art methods for securing modularsteering wheel and air bag assemblies to steering shafts.

[0011] In a further feature of this invention, the steering shaft isreceived within a fixed outer housing. The fixed outer housing has slotswhich provide access to the securement members in the hub. The slots arethus utilized to allow the steering wheel to be secured to the steeringshaft.

[0012] The removal structure preferably is also aligned with an accessopening. The access opening for the removal structure may be permanentlyaccessible. To remove the wheel, the removal structure is actuated tobreak the wedge lock. However, unless the securement structure has beenpreviously removed, the removal structure cannot remove the wheel as thesecurement structure prevents movement of the steering wheel relative tothe steering shaft.

[0013] The slots on the outer housing are selected such that when thesteering shaft is locked, as is the case when the ignition keys areremoved from the vehicle, the securement members in the hub are notaligned with the slots in the outer housing. Thus, a thief does not haveeasy access to the securement location on the steering wheel, and theftof the steering wheel and air bag is less likely.

[0014] These and other features of the present invention can be bestunderstood from the following specification and drawings, the followingof which is a brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1A shows a steering wheel incorporated into the presentinvention.

[0016]FIG. 1B is an assembly view of a connection according to thepresent invention.

[0017]FIG. 1C shows an inventive steering shaft according to the presentinvention.

[0018]FIG. 2 shows the steering wheel prior to attachment to a steeringshaft.

[0019]FIG. 3 shows the attachment of the steering wheel to the steeringshaft.

[0020]FIG. 4 shows structure for removing the steering wheel from thesteering shaft.

[0021]FIG. 5A shows an anti-theft feature of the present invention.

[0022]FIG. 5B shows the assembled anti-theft structure of FIG. 5A.

[0023]FIG. 6A is a cutaway partial view showing the use of theanti-theft structure.

[0024]FIG. 6B is a cross-sectional view showing the subject matter ofFIG. 6A.

[0025]FIG. 6C is a schematic view of a structure for locking a steeringshaft at a predetermined location.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0026] A steering wheel 20 is illustrated in FIG. 1A having a body 21including a hub boss 22 extending away from a planar surface of the body21. An opening 24 extends into the boss 22 to provide access to aninterior tapered bore 26.

[0027] As shown in FIG. 1B, the steering shaft 28 has an enlarged space30 extending to a slot 32 which connects the space 30 to the opposed end35 of the steering shaft 28. The securement structure for connecting thesteering wheel body 21 to the steering shaft 28 includes a taper pin 34having an opening 36 extending between an outer end 38 and an opposedinner end 40. Notably, opening 36 need not extend all the way throughpin 34 although that is preferred. Opening 36 need only be long enoughto receive pin 42. As can be appreciated from FIG. 1B, the pin 34 istapered and has a larger diameter at end 38 than it does at end 40.

[0028] Pin 34 is received in one side of opening 24. A pin 42 isexternally threaded at 44, and extends into an opposed side of theopening 24.

[0029]FIG. 1C shows the steering shaft 28. As can be appreciated, thereis a tapered surface 33 on the steering shaft 28 beneath the space 30and the slot 32.

[0030] The assembly of the steering wheel prior to attachment to thesteering shaft can be understood from FIG. 2. As can be seen in FIG. 2,pin 42 extends across the space 26 and into the taper pin 34. Threads 44are received in internal threads 49 within the taper pin 34. A wedged orangled surface 48 is formed in the boss 22, and the wedge extends towardan upper surface of the boss from end 46 towards an opposed end 48.

[0031] A removal portion 50 is also shown, and will be explained below.An air bag 51 is shown schematically such that it will be clear that thepresent invention is particularly useful for so-called modular steeringwheel and air bag arrangements, wherein the air bag is pre-assembled tothe steering wheel prior to the steering wheel being attached to thesteering shaft.

[0032] As can be appreciated in FIG. 2, a first securement member, pin42, extends across the space 46, and into a second securement member,taper pin 34. The taper pin 34 does not extend into the space 26 at thistime. The pin 42 is of a smaller size than the taper pin 34.

[0033]FIG. 3 shows the attachment of the steering shaft 28 to the boss22. The steering wheel body 21 is placed onto the steering shaft 28. Aninternally tapered surface 39 of the bore 26 moves onto the externallytapered portion 33.

[0034] The steering shaft moves into the opening 26 with the slot 32moving over the relatively small pin 42 until the pin 42 is receivedwithin space 30. At that time, pin 42 is driven to draw the taper pin 34into the space 26. Taper pin 34 has an outer diameter which is greaterthan the diameter of slot 32, and fits tightly within space 30. As canbe seen, a surface of the boss 22 and the surface of the opening 30which taper pin 34 rides along are both tapered. Thus, as the taper pin34 is drawn from the left to the right between the position of FIG. 2 tothe position of FIG. 3, the boss 22 is forced onto the steering shaft28. As this occurs, a wedge lock is achieved between the surfaces 33 and39. This wedge lock is sufficient to hold the steering wheel body 21 onthe steering shaft 28 even if one or both of the securement members 42,34 break or become loose.

[0035] Once secured, the steering shaft cannot rotate relative to thesteering wheel. This is true because the taper pin 34, pin 42, and thewedge lock created between the steering shaft and the steering wheel allrestrict rotation. It is also possible to add splines between thesteering wheel and the steering shaft to further prevent rotation,although this is not necessary.

[0036] A further feature of this invention is that the use of thesecurement structure and the slot 32 ensures proper rotational alignmentbetween the steering wheel and the steering shaft upon initial assembly.The securement structure, and in particular pin 42 must be aligned withthe slot 32 for this steering wheel to move onto the shaft. This ensuresthe steering wheel is at the proper rotational position relative to thesteering shaft, within a small number of degrees. This provides benefitsin increasing the ease and speed of aligning the steering wheel andsteering shaft when the second securment structure is drawn into place.

[0037] Thus, a simple and reliable method of attaching a steering wheelbody, which in particular may be a modular steering wheel assembly, ontoa steering shaft is disclosed. The securement structure is compact andinexpensive compared to the prior art.

[0038]FIG. 4 shows structure 50 for facilitating the removal of thesteering wheel from the steering shaft 28. As shown, structure 50includes a taper pin or wedge 52 having an angled surface 54 extendingbetween an end 56 and an opposed end 58. A threaded pin 60 is receivedin a portion 61 of the hub unthreaded and extends within the taper pin52. The taper pin 52 is drawn across the end surface 35 of the steeringshaft 28 when the pin 60 is turned. The wedge surface 54 forces the boss22 upwardly, and off of the steering shaft 28 during this movement. Thiswill break the wedge lock and allow removal of the steering shaft fromthe steering wheel. As will be explained below, the taper pin 34 and pin42 must be removed prior to the use of the removal structure 50.

[0039] Preferably, an access opening is provided through the housing orboss 22. this access opening will rotate with the wheel such that aworker will always be able to access the removal structure to assist inbreaking the wedge lock.

[0040]FIG. 5A shows another feature of the present invention. In FIG.5A, embodiment 60 includes a sleeve 62 extending from a steering columnbody 64. Sleeve 62 and body 64 are fixed, and steering shaft 28 rotateswith the steering wheel body 21 inside the sleeve 62 and the housing 64.As shown, slots 66 are formed in the sleeve 62.

[0041] As shown in FIG. 5B, when assembled, the slots 66 may be alignedwith the openings 24, or pin 42. This will facilitate the assembly ofthe steering wheel assembly onto the steering shaft. However, if thisstructure were left this way, then a thief would have access to thesecurement structure, and would be able to remove the steering wheelfrom the steering shaft.

[0042] As shown in FIG. 6A, taper pin 34 extends outwardly of slot 66prior to securement pin 42 being turned. This is further shown in FIG.6B. The taper pin 34 is preferably in this position when the wheel ismoved onto the steering shaft 28. The pin 42 may be turned to draw thetaper pin 34 into the space 30 in the steering shaft 28, as explainedabove.

[0043] The present invention ensures that the slots 66 are not alignedwith the pins 34, 42 or the opening 24, when the steering shaft 28 islocked. As shown in FIG. 6C, a steering column 28 is formed with aplurality of openings 76, one of which selectively receives a pin 78 tolock the steering column 28 at a predetermined position. Although shownschematically, the structure, such as spring 80 or cam, for biasing thepin 78 into one of the openings 76 is known. Essentially, the steeringshaft 28 is freely rotatable with the pin 78 removed from all of theopenings 76 while the ignition is on. However, when the ignition isturned off, the pin 78 moves into one of the openings 76 locking thewheel at one of a predetermined number of locations relative to thehousing 64. The present invention ensures that when the steering column28 is at any one of the possible positions in the locked state, theopening 24 is not aligned with the slot 66. Thus, when the vehicle isdeactivated and the steering wheel is locked, a thief will not haveaccess through the slot 66 into the securement structure for removal ofthe steering wheel.

[0044] The thief will still have access to the access opening forremoving the removal structure 50. However, the securement structurewould still secure the steering wheel to the steering shaft. Since thethief would not have access to the securement structure, the thief wouldnot be able to remove the securement structure. If the securementstructure has not been removed, then the removal structure would notmove the steering wheel off of the steering shaft.

[0045] Although a preferred embodiment of this invention has beendisclosed, a worker of ordinary skill in the art would recognize thatcertain modifications come within the scope of this invention. For thatreason, the following claims should be studied to determine the truescope and content of this invention.

1. A steering wheel comprising: a steering wheel body (21) having a bore(26) to receive a steering shaft (28), the steering wheel body having afirst securement member (42) connected to a spaced second securementmember (34), the first securement member extending across the bore, andthe first securement member having a first outer dimension which is lessthan an outer dimension of the second securement member, the secondsecurement member being operable to be drawn into the bore by the firstsecurement member; and the steering wheel body being secured to asteering shaft by drawing the second securement member into the bore. 2.A steering wheel as recited in claim 1, wherein the second securementmember is tapered, and moves along an angled surface to force thesteering wheel body further onto a steering shaft as the firstsecurement member draws the second securement member across said bore.3. A steering wheel as recited in claim 2, wherein the first securementmember is externally threaded (44) into an interior threaded bore (36)in the second securement member.
 4. A steering wheel as recited in claim3, wherein the tapered surface of the taper pin forces an externallytapered portion (33) of the steering shaft to have a wedge lock with aninternally tapered portion (39) of the steering wheel body.
 5. Asteering wheel as recited in claim 1, wherein a removal structure (50)is positioned in the steering wheel body and has a first and secondmember (60,52), with one of the first and second members having a wedgesurface for being drawn along an angled surface and forcing the steeringwheel body off of a steering shaft.
 6. A steering wheel as recited inclaim 1, wherein the steering wheel body is provided with an air bag(51) attached to a steering shaft when the steering wheel body isattached.
 7. A steering wheel and steering shaft assembly comprising: asteering shaft (28) for being attached to a steering wheel; a steeringwheel body (21) for being attached to the steering shaft; a securementassembly (34,42) for securing the steering wheel to the steering shaft;and a removal assembly (50) for forcing the steering wheel body upwardlyand off of the steering shaft when it is desired to remove the steeringwheel body, and after removal of the securement assembly.
 8. An assemblyas recited in claim 7, wherein the removal assembly includes one pin(52) which is drawn by another pin (60) to move along a surface on atleast one of the steering shaft and the steering wheel body, and forcethe steering wheel body off of the steering shaft.
 9. A steering wheeland steering shaft assembly comprising: a steering shaft (28) extendingfrom a first end remote from a steering wheel body (2) towards a secondend (35) adjacent to the steering wheel body, the steering shaft havinga slot (32) extending into an enlarged space (30), the slot having afirst dimension which is smaller than a dimension of the space; asteering wheel body (21) having a bore (26) to receive the steeringshaft, the steering wheel body having a first securement member (42)connected to a spaced second securement member (34), the firstsecurement member (42) extending across the space and the firstsecurement member having a second outer dimension which is less than thefirst dimension of the slot, such that the first securement member canmove through the slot and into the enlarged space, the first securementmember being operable to draw the second securement member into thespace, the second securement member having a third outer dimension whichis greater than the first dimension, such that the second securementmember secures the steering wheel on the steering shaft when drawn intothe space; and the first securement member passing through the slot andinto the space to initially position the steering wheel on the steeringshaft, and the first securement member then drawing the secondsecurement member into the space to lock the steering wheel on thesteering shaft.
 10. An assembly as recited in claim 9, wherein the slotextends from the space to the second end of the steering shaft.
 11. Anassembly as recited in claim 9, wherein an outer sleeve (62) is fixedand surrounds the steering shaft and a portion of the steering wheelbody, the outer sleeve (62) having slots (66) at circumferentiallyspaced locations, the slots providing access to the first and secondsecurement members.
 12. An assembly as recited in claim 11, wherein thesteering shaft being selectively locked (76) in at least one positionrelative to said sleeve, the slot not being aligned with the securementmembers when the steering shaft is locked in at least one position. 13.A steering wheel and steering shaft assembly comprising: a steeringshaft rotatable along an axis, the steering shaft being surrounded by afixed housing, the housing including a sleeve including a slot in atleast one location, and the steering shaft being selectively locked at acircumferential location within the housing; a steering wheel assemblyattached to the steering shaft, the steering wheel assembly having anattachment location in a side of the steering wheel assembly, the slotbeing selectively aligned with the attachment location to allowattachment and removal of the steering wheel body to the steering shaft;and the attachment location being circumferentially spaced from the slotwhen the steering column is locked.
 14. An assembly as recited in claim13, wherein the attachment location includes a pair of spaced openings(24) on opposed sides of a boss in the steering wheel, and securementmembers inserted into each of the spaced openings.
 15. An assembly asrecited in claim 13, wherein there are two spaced slots in the sleevewith one of the securement members being removable through each of theslots.
 16. A method of securing a steering wheel to a steering shaftcomprising the steps of: (1) providing a steering shaft (28) having aslot (32) extending from an end (35) of the steering shaft to a space(30), the slot having a first dimension which is smaller than thedimension of the space, a steering wheel body having a boss (22) to bereceived on the steering shaft, a securement structure including a firstsecurement member (42) of a second dimension, the second diameter beingsmaller than the first dimension, and providing a second securementmember (34), the second securement member having an outer dimensionwhich is greater than the first dimension, the first securement memberbeing operable to draw the second securement member into the space; (2)placing the first securement member in the boss in the steering wheelbody, the first securement member extending across the boss; (3) movingthe steering wheel body onto the steering shaft with the firstsecurement member moving through the slot and into the space; (4)drawing the second securement member into the space.
 17. A method asrecited in claim 16, wherein the first securement member is externallythreaded (44) and received in an internally threaded bore (36) in thesecond securement member, the first connection member being turned todraw the second connection member into the space.
 18. A method asrecited in claim 16, wherein said securement structure is aligned with aslot prior to moving the steering wheel body onto the steering wheelshaft, such that the steering wheel body is initially easily alignedwith the steering shaft within a few degrees, and upon drawing thesecond securment member into place, the steering wheel body iscompletely aligned with the steering shaft.